Valve stoppers are used in particular to close filling and checking holes in storage batteries, in particular in lead-acid batteries for motor vehicles. The valve elements fitted in the valve stopper are designed to allow gas to escape, should excess pressure arise in the battery case.
It is known from EP 1 194 962 B1, for example, to place a resilient cap onto a tubular neck, which defines a container opening in a battery cell. A separate closing cover sealing the battery lid is positioned above the resilient cap. In the event of excess pressure, gas may escape from inside the cell to the outside through the interspace between tubular neck and resilient cap due to the resilient deformability of the resilient cap.
EP 1 001 905 B1 discloses a sealing valve of rubber-elastic material with a stopper member, which may be introduced into a container opening as far as a stopper collar projecting radially beyond the stopper member. At least one control channel is fashioned on the stopper member in the form of a recess in the stopper member, which channel extends in the direction of the longitudinal axis of the sealing valve from the bottom of the stopper member as far as the stopper collar. A sealing bead is formed on the stopper collar, which bead may be placed sealingly onto a container edge enclosing the container opening. In addition, the control channel in the stopper member is extended as far as the sealing bead.
DE 103 49 395 B3 discloses a valve stopper in which a valve of a resilient material is formed in one piece on a base body, such that the valve and the base body form a multicomponent injection molding. The one-piece resilient valve in the form of a molding has a valve body and a sealing tab formed thereon, which is thinner in cross section than the valve body. The sealing tab is formed at the lower outer edge area of the valve body and takes the form of a semicircular disc, which rests for sealing purposes against the inner edge of a sleeve in the valve body.